continue;
 
                if (S_ISDIR(entry.mode)) {
-                       obj = &lookup_tree(entry.oid)->object;
-                       if (name)
+                       obj = (struct object *)lookup_tree(entry.oid);
+                       if (name && obj)
                                put_object_name(options, obj, "%s%s/", name,
                                        entry.path);
                        result = options->walk(obj, OBJ_TREE, data, options);
                }
                else if (S_ISREG(entry.mode) || S_ISLNK(entry.mode)) {
-                       obj = &lookup_blob(entry.oid)->object;
-                       if (name)
+                       obj = (struct object *)lookup_blob(entry.oid);
+                       if (name && obj)
                                put_object_name(options, obj, "%s%s", name,
                                        entry.path);
                        result = options->walk(obj, OBJ_BLOB, data, options);
                case S_IFREG | 0664:
                        if (!options->strict)
                                break;
+                       /* fallthrough */
                default:
                        has_bad_modes = 1;
                }
                buffer += 41;
                parent_line_count++;
        }
-       graft = lookup_commit_graft(commit->object.oid.hash);
+       graft = lookup_commit_graft(&commit->object.oid);
        parent_count = commit_list_count(commit->parents);
        if (graft) {
                if (graft->nr_parent == -1 && !parent_count)
                enum object_type type;
 
                buffer = to_free =
-                       read_sha1_file(tag->object.oid.hash, &type, &size);
+                       read_object_file(&tag->object.oid, &type, &size);
                if (!buffer)
                        return report(options, &tag->object,
                                FSCK_MSG_MISSING_TAG_OBJECT,
                        ret = report(options, &tag->object,
                                FSCK_MSG_TAG_OBJECT_NOT_TAG,
                                "expected tag got %s",
-                           typename(type));
+                           type_name(type));
                        goto done;
                }
        }